JP2010089786A

JP2010089786A - Seedling transplanting machine

Info

Publication number: JP2010089786A
Application number: JP2010003918A
Authority: JP
Inventors: Masabumi Saeki; 正文佐伯; Hitoshi Yamazaki; 仁史山崎; Manabu Namoto; 学名本; Takuya Okada; 岡田　　卓也; Mitsuo Konda; 満夫根田; Daisuke Imaizumi; 大介今泉; Kazuhiko Ishii; 和彦石井
Original assignee: Iseki and Co Ltd; Iseki Agricultural Machinery Mfg Co Ltd
Current assignee: Iseki and Co Ltd; Iseki Agricultural Machinery Mfg Co Ltd
Priority date: 2010-01-12
Filing date: 2010-01-12
Publication date: 2010-04-22
Anticipated expiration: 2026-05-30
Also published as: JP5018897B2

Abstract

<P>PROBLEM TO BE SOLVED: To easily constituting a mechanism for automatically lowering rear wheels for correcting a longitudinal inclining attitude of a machine body by restraining a weight increase and a cost increase in the machine body. <P>SOLUTION: This seedling transplanting machine is constituted by arranging a vehicle body having right-left front wheels and the right-left rear wheels 4, arranging a liftable seedling transplanting part in the rear of the vehicle body, arranging a rear wheel transmission case 34 having a rear wheel shaft 56 and a rear wheel transmission shaft 33 for transmitting from the front side to an input shaft 34b of the rear wheel transmission case 34, vertically rotatably installing the rear wheel transmission case 34 around a rotary fulcrum shaft 54 so that the rear wheel shaft 56 is positioned on the rear side of the rotary fulcrum shaft 54, arranging a compression spring for energizing the rotational movement to the lower side of the rear wheel transmission case 34, arranging regulating members 57 and 58 for regulating a rotational movement area in the vertical direction of the rear wheel transmission case 34, and winding the compression spring around the outer periphery of the regulating members 57 and 58. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、後輪を備える苗移植機に関する。 The present invention relates to a seedling transplanter including a rear wheel.

従来、乗用型田植機の走行車輌では、例えば、左右の後輪を上下揺動自在に支持し、旋回時に機体後部の苗植付部を田面から所定の非作業位置まで上昇させると、この上昇操作に連動して左右の後輪を下降させることにより、機体の後部を持ち上げて機体を前下がり気味にすることで、機体の旋回が円滑に行えるようにしている（特許文献１参照。）。 Conventionally, in a traveling vehicle of a riding type rice transplanter, for example, when the left and right rear wheels are supported so as to be able to swing up and down, and the seedling planting portion at the rear of the aircraft is raised from the rice field to a predetermined non-working position when turning, this rise By lowering the left and right rear wheels in conjunction with the operation, the rear part of the aircraft is lifted to make the aircraft appear to be lowered forward (see Patent Document 1).

特開２００４−２７５０５９号公報JP 2004-275059 A

上記従来の機体後部の持ち上げは、植付部の上下に連動した構成であり、植付部を上昇させると、前後進に関係なく作動するため、後進により畦越えするときやアユミを登る場合、逆にバランスを悪くする問題があった。また、植付部を下げた植付作業時は機体後部の持ち上げが不可能な為、機体が前上がり姿勢になったり、苗の植付姿勢が悪化する問題がある。 The above-mentioned conventional lifting of the rear part of the fuselage is a structure that is linked to the top and bottom of the planting part, and when the planting part is raised, it operates regardless of forward and backward movement, so when going over the heel by reverse traveling or climbing Ayumi, On the other hand, there was a problem of poor balance. In addition, since the rear part of the aircraft cannot be lifted during the planting operation with the planting part lowered, there is a problem that the aircraft is in a front-up posture or the seedling planting posture is deteriorated.

本発明では、機体の前後傾斜姿勢を修正するために自動的に後輪を下降させる機構を、機体の重量アップやコストアップを抑えて簡単に構成することにある。 In the present invention, a mechanism for automatically lowering the rear wheels to correct the front / rear tilt posture of the airframe is configured simply by suppressing an increase in weight and cost of the airframe.

この発明は、上記課題を解決するべく次のような技術的手段を講じた。
すなわち、請求項１に係る発明は、左右の前輪（３）及び左右の後輪（４）を備える車体（２）を設け、該車体（２）の後方には昇降可能な苗植付部（７）を設け、後輪車軸（５６）を備える後輪伝動ケース（３４）と該後輪伝動ケース（３４）の入力軸（３４ｂ）へ前側から伝動する後輪伝動軸（３３）とを設け、回動支点軸（５４）より後側に後輪車軸（５６）が位置するように前記後輪伝動ケース（３４）を前記回動支点軸（５４）回りに上下に回動可能に装着し、後輪伝動ケース（３４）の下側への回動を付勢する圧縮スプリングを設け、後輪伝動ケース（３４）の上下方向の回動域を規制する規制部材（５７，５８）を設け、前記圧縮スプリングを規制部材（５７，５８）の外周に巻回する構成とした苗移植機とした。 In order to solve the above problems, the present invention has taken the following technical means.
That is, the invention according to claim 1 is provided with a vehicle body (2) provided with left and right front wheels (3) and left and right rear wheels (4), and a seedling planting portion that can be raised and lowered behind the vehicle body (2) ( 7), a rear wheel transmission case (34) having a rear wheel axle (56) and a rear wheel transmission shaft (33) that is transmitted from the front side to the input shaft (34b) of the rear wheel transmission case (34) are provided. , rotation fulcrum shaft (54) the rotation fulcrum shaft (54) pivotally mounted vertically around the rear wheel transmission case as the rear wheel axle (56) is located (34) to the rear side than the A compression spring is provided to urge the rear wheel transmission case (34) to turn downward, and restriction members (57, 58) are provided to restrict the vertical rotation area of the rear wheel transmission case (34). The seedling transplanting machine is configured such that the compression spring is wound around the outer periphery of the regulating member (57, 58) .

この苗移植機において、機体の前進での畦越え時、前進でのトラックへの積込時あるいは耕盤が深い圃場での前進時において、後輪４に所定以上の駆動負荷が生じたときには、その駆動反力により後輪伝動ケース３４が下側に回動して後輪４が下動状態となり、機体が前上がり姿勢になって前輪３が浮き上がったりするのを防止できる。 In this seedling transplanter, when beyond ridge in advance of the aircraft, during forward movement in the loading or during plowing machine deep field in the track in advance, when the driving load more than a predetermined rear wheel 4 occurs, The driving reaction force causes the rear wheel transmission case 34 to rotate downward and the rear wheel 4 to move downward, preventing the vehicle body from being lifted forward and the front wheel 3 from being lifted .

請求項１に係る発明によると、機体の前進での畦越え時、前進でのトラックへの積込時あるいは耕盤が深い圃場での前進時は、駆動反力により後輪４が下動状態となり、機体が前上がり姿勢になって前輪３が浮き上がったり、あるいは苗移植機の走行車輌においては苗の植付姿勢が悪化したりするような事態を未然に防止することができる。また、圧縮スプリングを規制部材５７，５８の外周に巻回する構成としたので、圧縮スプリングの外れを防止できると共に、構成の簡略化が図れる。 According to the first aspect of the present invention, the rear wheel 4 is moved downward by the driving reaction force when the aircraft is moving forward over the ridge, when it is loaded onto the truck or when it is advanced in the field where the cultivator is deep. Thus, it is possible to prevent a situation in which the machine body is in a forwardly raised posture and the front wheel 3 is lifted, or in a traveling vehicle of the seedling transplanter , the seedling planting posture is deteriorated. In addition, since the compression spring is wound around the outer periphery of the regulating members 57 and 58, the compression spring can be prevented from coming off and the configuration can be simplified.

田植機の側面図Side view of rice transplanter 田植機の平面図Top view of rice transplanter 前輪を示す側面図Side view showing the front wheels 施肥装置の一部及び後輪伝動ケースを示す背面図Rear view showing part of fertilizer application and rear wheel transmission case 後輪伝動ケースを示す側面図Side view of rear wheel transmission case

この発明の実施の一形態の苗移植機を以下に説明する。
図１及び図２は、走行車輌を備える乗用型の４条植田植機（苗移植機）１を示すものであり、車体２の前後には走行車輪としての左右一対の前輪３及び後輪４が架設されている。車体上前部には操作ボックス５及びステアリングハンドル６等を有する操縦装置が設置され、また、車体２の後方には昇降可能な苗植付部７が装備されている。また、車体２の後部には施肥装置８が設けられ、肥料タンク９に貯留する肥料を各条の繰出部１０で所定量づつ繰り出し、その繰り出した肥料をブロア１１からの圧力風により各条の移送ホース１２で苗植付部７に設けた吐出口１３から吐出して施肥する構成となっている。操縦装置の後側に運転席１４が設置され、運転席１４の下側に田植機の各部に動力を伝達するエンジン１５が搭載されている。 A seedling transplanter according to an embodiment of the present invention will be described below.
FIG. 1 and FIG. 2 show a riding type 4-row transplanter (seedling transplanter) 1 having a traveling vehicle. A pair of left and right front wheels 3 and rear wheels 4 as traveling wheels are provided in front of and behind a vehicle body 2. Is built. A steering device having an operation box 5 and a steering handle 6 is installed at the front upper part of the vehicle body, and a seedling planting part 7 that can be moved up and down is provided at the rear of the vehicle body 2. Further, a fertilizer application device 8 is provided at the rear of the vehicle body 2, and the fertilizer stored in the fertilizer tank 9 is fed out by a predetermined amount by the feeding unit 10 of each strip, and the fed fertilizer is fed to each strip by the pressure air from the blower 11. It is the structure which discharges from the discharge port 13 provided in the seedling planting part 7 with the transfer hose 12, and fertilizes. A driver's seat 14 is installed on the rear side of the control device, and an engine 15 that transmits power to each part of the rice transplanter is mounted below the driver's seat 14.

前記ステアリングハンドル６は、この回動操作によりステアリングポスト内のステアリング軸からステアリングケース内を経て減速回転される出力軸、ピットマンア−ム及び操向ロッド等を介して左右の前輪３を操向させ操舵するようになっている。 The steering handle 6 is steered by steering the left and right front wheels 3 via an output shaft, a pitman arm, a steering rod, and the like that are decelerated and rotated from the steering shaft in the steering post through the steering case. It is supposed to be.

前輪３は、複数本（３本）のスポーク３ａを備え、各スポーク３ａ間となる内部に空間を備えているため、機体の走行で該空間に入る泥土をスポーク３ａが持ち上げて圃場を荒らすことがある。そこで、前記空間を遮るホイルデイスクを前輪２に取り付けてスポーク３ａによる泥土の持ち上げを防止する構成が知られているが、ホイルデイスクに泥土が付着し、その泥土が落下して圃場を荒らしたり走行抵抗になるおそれがある。特に、前輪３の回転に伴うホイルデイスクの回転中心部は回転移動量が少ないため、泥土の付着量が多くなる。そこで、図３に示すホイルデイスク１６は、中央部に円形の孔１６ａを設け、泥土の付着量の多いホイルデイスクの回転中心部を欠如した構成としたので、スポーク３ａによる泥土の持ち上げを防止しつつ、ホイルデイスク１６への泥土の付着を抑えることができ、ホイルデイスク１６に泥土が付着して圃場を荒らしたり走行抵抗になったりするようなことを防止できる。 Since the front wheel 3 includes a plurality of (three) spokes 3a and has a space inside each of the spokes 3a, the spoke 3a lifts up the mud that enters the space and causes the field to be roughened by running the aircraft. There is. Therefore, a configuration is known in which a foil disk that blocks the space is attached to the front wheel 2 to prevent the mud from being lifted by the spokes 3a. However, mud adheres to the wheel disk, and the mud falls to roughen the field and run. There is a risk of resistance. In particular, since the rotational center of the wheel disk accompanying the rotation of the front wheel 3 has a small amount of rotational movement, the amount of mud adhering increases. Therefore, the wheel disk 16 shown in FIG. 3 has a circular hole 16a at the center and lacks the center of rotation of the wheel disk with a large amount of mud adhering to prevent the mud from being lifted by the spoke 3a. On the other hand, it is possible to prevent the mud from adhering to the wheel disk 16, and it is possible to prevent the mud from adhering to the wheel disk 16 from damaging the farm field or causing running resistance.

苗植付部７は、車体２の後部に昇降リンク機構１７を介して昇降可能に装着され、昇降用油圧シリンダ１８の伸縮作動により昇降する構成であり、本例では、油圧シリンダ１８の引き側で苗植付部７を上昇させる構成としている。なお、１９は植付昇降レバーを示す。 The seedling planting part 7 is mounted on the rear part of the vehicle body 2 through a lifting link mechanism 17 so as to be lifted and lowered by a telescopic operation of the lifting hydraulic cylinder 18, and in this example, the pulling side of the hydraulic cylinder 18 is arranged. It is set as the structure which raises the seedling planting part 7 by. Reference numeral 19 denotes a planting lift lever.

また、この苗植付部７には、左右に往復動する苗載タンク２０、１株分の苗を切取って土中に植込む植込杆２１を有する植付装置２２、苗植付面を滑走しながら整地するフロ−ト（サイドフロ−ト）２３、センタフロ−ト２４等を備えている。 The seedling planting section 7 includes a seedling mounting tank 20 that reciprocates left and right, a planting device 22 having a planting basket 21 for cutting out seedlings for one stock and planting them in the soil, a seedling planting surface A float (side float) 23, a center float 24, and the like that level the ground while sliding are provided.

エンジン１５の回転動力は、エンジン出力プーリ２５からベルト２６を介して油圧式無段変速装置（ＨＳＴ）２７の入力プ−リ２８、入力軸２９に伝えられ、この入力軸２９からこれと同一軸芯上に設けられた伝動軸を介して油圧ポンプを駆動するようになっており、更に、油圧式無段変速装置２７の出力軸からミッションケ−ス３０のミッション入力軸に伝えられるようになっている。 The rotational power of the engine 15 is transmitted from an engine output pulley 25 to an input pulley 28 and an input shaft 29 of a hydraulic continuously variable transmission (HST) 27 via a belt 26. The hydraulic pump is driven via a transmission shaft provided on the core, and further, the hydraulic pump is transmitted from the output shaft of the hydraulic continuously variable transmission 27 to the mission input shaft of the mission case 30. ing.

操作ボックスすなわちフロントカバー５の上部近傍には、該油圧式無段変速装置２７を駆動する変速レバ−３１が配置され、この変速レバ−３１の前後方向の操作で油圧式無段変速装置２７を駆動し機体の前進及び後進制御を司るように構成されている。運転席１４の前方右側には、前輪３及び後輪４を制動するためのブレーキペダル３２を設けている。また、このブレーキペダル３２を踏み込み操作状態（制動状態）で保持できるペダル保持装置を設けている。 A shift lever 31 for driving the hydraulic continuously variable transmission 27 is disposed in the vicinity of the upper portion of the operation box, that is, the front cover 5, and the hydraulic continuously variable transmission 27 is operated by operating the shift lever 31 in the front-rear direction. It is configured to drive and manage forward and backward control of the airframe. A brake pedal 32 for braking the front wheel 3 and the rear wheel 4 is provided on the front right side of the driver seat 14. Further, a pedal holding device is provided that can hold the brake pedal 32 in a depressed operation state (braking state).

ミッションケース３０内からの動力により、苗植付部７が作動すると共に、該ミッションケース３０の左右両側に設けた前輪３が駆動する。また、ミッションケース３０内からの動力が左右各々の後輪伝動軸３３を介して左右の後輪伝動ケース３４内へ伝動され、後輪４が駆動する。 The seedling planting unit 7 is operated by the power from within the mission case 30 and the front wheels 3 provided on the left and right sides of the mission case 30 are driven. The power from the transmission case 30 is transmitted to the left and right rear wheel transmission cases 34 via the left and right rear wheel transmission shafts 33, and the rear wheels 4 are driven.

左側の後輪伝動ケース３４の左右方向内側（右側）には、該ケース３４から出力される左右方向のロータ用出力軸３５を設けている。このロータ用出力軸３５から該軸３５回りに上下回動自在のロータ駆動用ケース３６及びロータ伝動軸３７を介して車体２の後側で且つ苗植付部７の前側に設けた整地ロータ３８へ伝動し、該整地ロータ３８の駆動により植付前の圃場を整地する構成となっている。一方、右側の後輪伝動ケース３４の左右方向内側（左側）には、該ケース３４から出力される左右方向の施肥用出力軸３９を設けている。この施肥用出力軸３９から該軸３９と一体回転する駆動クランクアーム４０、駆動ロッド４１及び従動アーム４２を介して施肥駆動軸４３へ該軸４３が往復回動するよう伝動され、この施肥駆動軸４３から各２条毎の入力アーム４４、ロッド４５、出力アーム４６及び一方向クラッチ４７等で構成される施肥伝動機構４８を介して該施肥伝動機構４８の左右に設けた各々の繰出部１０へ伝動し、該繰出部１０内の繰出ロータを一方向へ所定角度づつ回転させる構成となっている。このように、左右の後輪伝動ケース３４から整地ロータ３８及び施肥装置８の繰出部１０へ伝動するにあたり、一方の後輪伝動ケース３４から整地ロータ３８へ伝動し、他方の後輪伝動ケース３４から繰出部１０へ伝動する構成として、それぞれの伝動出力を左右で振り分けた構成としたので、左右の後輪伝動ケース３４内の伝動負荷の均一化が図れ、ひいては左右の後輪４の駆動力の均一化が図れて機体の走行性能及び直進性能が向上する。また、整地ロータ３８及び施肥装置８の繰出部１０への伝動機構を交錯させずに簡潔に構成できる。 A left-right rotor output shaft 35 that is output from the case 34 is provided on the inner side (right side) of the left rear wheel transmission case 34 in the left-right direction. A leveling rotor 38 provided on the rear side of the vehicle body 2 and on the front side of the seedling planting portion 7 through a rotor driving case 36 and a rotor transmission shaft 37 that can be rotated up and down around the shaft 35 from the rotor output shaft 35. The ground before the planting is leveled by driving the leveling rotor 38. On the other hand, an output shaft 39 for fertilization in the left-right direction output from the case 34 is provided on the inner side (left side) in the left-right direction of the rear wheel transmission case 34 on the right side. The fertilizer output shaft 39 is transmitted to the fertilizer drive shaft 43 through a drive crank arm 40, a drive rod 41 and a driven arm 42 that rotate integrally with the shaft 39 so as to reciprocate and rotate. 43 to each feeding section 10 provided on the left and right of the fertilization transmission mechanism 48 via a fertilization transmission mechanism 48 constituted by the input arm 44, the rod 45, the output arm 46, the one-way clutch 47, etc. Transmission is configured to rotate the feeding rotor in the feeding unit 10 in one direction at a predetermined angle. In this way, when transmitting from the left and right rear wheel transmission cases 34 to the leveling rotor 38 and the feeding portion 10 of the fertilizer application device 8, transmission is performed from one rear wheel transmission case 34 to the leveling rotor 38 and the other rear wheel transmission case 34 is transmitted. As the structure for transmitting the power to the feeding section 10, the transmission outputs are distributed to the left and right, so that the transmission load in the left and right rear wheel transmission cases 34 can be made uniform, and consequently the driving force of the left and right rear wheels 4. And the running performance and straight running performance of the aircraft are improved. Moreover, it can comprise simply, without making the transmission mechanism to the feeding part 10 of the leveling rotor 38 and the fertilizer applicator 8 cross.

車体１の後部に設けた左右方向に延びる後部フレーム４９の左右両端部には、プレートで構成される左右方向内側の第一支持部材５０と左右方向外側の第二支持部材５１とを各々設けている。前記第一支持部材５０及び第二支持部材５１は後部フレーム４９から下側に延設され、第一支持部材５０は後部フレーム４９に溶接して固定され、第二支持部材５１は後部フレーム４９の端部に設けたブラケット５２に前後上下計４本の取付ボルト５３により着脱可能に装着されている。第一支持部材５０の下端部には左右方向外側に延びる回動支点軸５４を溶接して固定し、第二支持部材５１の下端部には前記回動支点軸５４の端部を挿入する孔５１ａを設けている。従って、回動支点軸５４は、第一支持部材５０と第二支持部材５１とで両持ち支持されている。これにより、回動支点軸５４の支持が安定し、該軸５４のガタを抑えることができ、後述する後輪４の上下動を適正に且つ安定して行える。左右方向で第一支持部材５０と第二支持部材５１との間には、後部フレーム４９から後方に延びる背面視Ｕ字型の第三支持部材５５を設けている。前記取付ボルト５３により第二支持部材５１を後部フレーム４９に対して着脱可能に構成しているので、第二支持部材５１を取り外して第一支持部材５０で片持ち支持される回動支点軸５４に沿って機体の左右方向外側から後輪伝動ケース３４の着脱を容易に行える。 A first support member 50 on the inner side in the left-right direction and a second support member 51 on the outer side in the left-right direction are provided on the left and right ends of the rear frame 49 provided in the rear portion of the vehicle body 1 and extending in the left-right direction. Yes. The first support member 50 and the second support member 51 extend downward from the rear frame 49, the first support member 50 is fixed by welding to the rear frame 49, and the second support member 51 is attached to the rear frame 49. A bracket 52 provided at the end is detachably mounted by four mounting bolts 53 in total, front and rear. A rotation fulcrum shaft 54 extending outward in the left-right direction is fixed to the lower end portion of the first support member 50 by welding, and a hole for inserting the end portion of the rotation fulcrum shaft 54 into the lower end portion of the second support member 51. 51a is provided. Therefore, the rotation fulcrum shaft 54 is supported at both ends by the first support member 50 and the second support member 51. As a result, the support of the rotation fulcrum shaft 54 is stabilized, the backlash of the shaft 54 can be suppressed, and the vertical movement of the rear wheel 4 described later can be performed appropriately and stably. Between the first support member 50 and the second support member 51 in the left-right direction, a third U-shaped third support member 55 extending rearward from the rear frame 49 is provided. Since the second support member 51 is configured to be detachable from the rear frame 49 by the mounting bolt 53, the rotation fulcrum shaft 54 that is cantilevered by the first support member 50 by removing the second support member 51. The rear wheel transmission case 34 can be easily attached and detached from the outside in the left-right direction of the aircraft.

後輪伝動ケース３４は、回動支点軸５４を挿入するための孔及び後輪車軸５６を挟む位置で分割する上下の分割ケース３４ａからなる構成であり、左右の後輪伝動ケース３４で共用化されている。尚、前記孔より後輪車軸５６は後側に位置している。上側の分割ケース３４ａの左右内側には規制用ピン５７を設け、該規制用ピン５７が挿入される長孔５８ａを備える規制用アーム５８が、前記第三支持部材５５の側面に設けた支持軸５９回りに回動自在に設けられている。従って、前記規制用ピン５７の移動が前記長孔５８ａ内で規制され、後輪伝動ケース３４の上下回動域が規制される。従って、前記規制用ピン５７及び規制用アーム５８は、後輪伝動ケース３４の上下方向の回動域を規制する規制部材となる。また、第三支持部材５５の下面には弾性部材となるクッションゴム６０を設けており、このクッションゴム６０が後輪伝動ケース３４に接触することにより、後輪４からの振動を吸収する構成となっている。 The rear wheel transmission case 34 includes a hole for inserting the rotation fulcrum shaft 54 and an upper and lower divided case 34 a that is divided at a position sandwiching the rear wheel axle 56, and is shared by the left and right rear wheel transmission cases 34. Has been. The rear wheel axle 56 is located on the rear side of the hole. A restriction pin 57 is provided on the left and right inner sides of the upper divided case 34 a, and a restriction arm 58 having a long hole 58 a into which the restriction pin 57 is inserted is provided on a side surface of the third support member 55. It is provided so as to be rotatable around 59. Therefore, the movement of the restriction pin 57 is restricted in the elongated hole 58a, and the vertical rotation area of the rear wheel transmission case 34 is restricted. Therefore, the restriction pin 57 and the restriction arm 58 serve as restriction members for restricting the vertical rotation area of the rear wheel transmission case 34. Further, a cushion rubber 60 serving as an elastic member is provided on the lower surface of the third support member 55, and the cushion rubber 60 contacts the rear wheel transmission case 34 to absorb vibration from the rear wheel 4. It has become.

よって、後輪伝動ケース３４は回動支点軸５４回りに上下回動可能に構成され、後進時及び前進時でも後輪４の駆動負荷が小さい通常の走行時には、機体の自重で規制用アーム５８の長孔５８ａの上端に規制用ピン５７が当たる位置まで後輪伝動ケース３４が上動して後輪４が最上状態となる。このとき、後輪伝動ケース３４はクッションゴム６０に当接し、機体の振動が抑えられる。一方、前進時で後輪４に所定以上の駆動負荷が生じたときには、その駆動反力により機体の自重に抗して後輪伝動ケース３４が下側へ回動して後輪４が下動する。この後輪４の下動は、規制用アーム５８の長孔５８ａの下端に規制用ピン５７が当たることにより、最下位置が規制される。 Therefore, the rear wheel transmission case 34 is configured to be able to rotate up and down around the rotation fulcrum shaft 54, and during normal traveling where the driving load of the rear wheel 4 is small even when moving backward and forward, the regulating arm 58 is driven by the weight of the airframe. The rear wheel transmission case 34 moves up to the position where the restriction pin 57 hits the upper end of the long hole 58a, and the rear wheel 4 is in the uppermost state. At this time, the rear wheel transmission case 34 abuts against the cushion rubber 60 and vibrations of the airframe are suppressed. On the other hand, when a driving load exceeding a predetermined value occurs on the rear wheel 4 during forward movement, the rear wheel transmission case 34 rotates downward against the dead weight of the fuselage by the driving reaction force, causing the rear wheel 4 to move downward. To do. The downward movement of the rear wheel 4 is regulated at the lowest position by the regulation pin 57 hitting the lower end of the long hole 58a of the regulation arm 58.

尚、回動支点軸５４は、後輪４の外径内に設定している。従って、回動支点軸５４と後輪車軸５６との間隔を小さく設定しているので、後輪４の駆動反力で後輪伝動ケース３４を下側へ回動させることができるのである。 The rotation fulcrum shaft 54 is set within the outer diameter of the rear wheel 4. Accordingly, since the distance between the rotation fulcrum shaft 54 and the rear wheel axle 56 is set small, the rear wheel transmission case 34 can be rotated downward by the driving reaction force of the rear wheel 4.

ところで、後輪伝動軸３３は、ミッションケース３０に近い前部と後輪伝動ケース３４に近い後部とに自由な方向へ屈曲自在な継ぎ手（ユニバーサルジョイント）３３ａを備え、後輪伝動ケース３４の上下回動による該後輪伝動ケース３４の入力軸３４ｂの移動に順応する構成となっている。そして、後輪伝動ケース３４の回動で大きく屈曲変化する後側の継ぎ手３３ａにおいて、後輪車軸５６が最上位置となるべく後輪伝動ケース３４が上側に回動したとき前記継ぎ手３３ａが上側に凹となるよう屈曲し、後輪車軸５６が最下位置となるべく後輪伝動ケース３４が下側に回動したとき前記継ぎ手３３ａが下側に凹となるよう屈曲し、後輪伝動ケース３４の上下回動において後輪伝動軸３３の屈曲方向を互いに逆側にして上下に振り分けた構成としている。従って、後輪伝動ケース３４の上下回動全域において、継ぎ手３３ａの屈曲角度を許容範囲内で極力小さく設定できるため、後輪伝動軸３３による伝動ロスを低減できて後輪伝動ケース３４ヘの伝動を良好にできる。また、後輪車軸５６が最下となるときの後輪伝動軸３３の継ぎ手３３ａの屈曲角度より後輪車軸５６が最上となるときの後輪伝動軸３３の継ぎ手３３ａの屈曲角度が小さくなる構成としたので、後進時や前進時でも後輪４の駆動負荷が小さい通常走行時には、機体の自重により後輪伝動ケース３４が上側へ回動して後輪車軸５６が最上位置となるため、継ぎ手３３ａの屈曲角度が小さく、該後輪伝動軸３３による伝動ロスを低減できて後輪伝動ケース３４ヘの伝動を良好にできる。 By the way, the rear wheel transmission shaft 33 includes a joint (a universal joint) 33a that can be freely bent at a front portion near the transmission case 30 and a rear portion near the rear wheel transmission case 34. The structure adapts to the movement of the input shaft 34b of the rear wheel transmission case 34 by rotation. Then, in the rear joint 33a that is greatly bent and changed by the rotation of the rear wheel transmission case 34, when the rear wheel transmission case 34 is rotated upward as much as possible, the joint 33a is recessed upward. When the rear wheel transmission case 34 is rotated downward as much as possible so that the rear wheel axle 56 is at the lowest position, the joint 33a is bent so as to be concave downward, and the rear wheel transmission case 34 is In the rotation, the rear wheel transmission shaft 33 is arranged in the vertical direction with the bending directions opposite to each other. Therefore, since the bending angle of the joint 33a can be set as small as possible within the permissible range in the entire vertical rotation range of the rear wheel transmission case 34, transmission loss due to the rear wheel transmission shaft 33 can be reduced, and transmission to the rear wheel transmission case 34 can be achieved. Can be improved. Further, the bending angle of the joint 33a of the rear wheel transmission shaft 33 when the rear wheel axle 56 is at the uppermost position is smaller than the bending angle of the joint 33a of the rear wheel transmission shaft 33 when the rear wheel axle 56 is at the lowermost position. Therefore, during normal traveling where the driving load of the rear wheel 4 is small even when the vehicle is moving backward or forward, the rear wheel transmission case 34 is rotated upward due to the weight of the fuselage and the rear wheel axle 56 is at the uppermost position. The bending angle of 33a is small, transmission loss due to the rear wheel transmission shaft 33 can be reduced, and transmission to the rear wheel transmission case 34 can be improved.

以上により、この田植機１により、直進植付時において、通常の走行負荷のときは後輪４が最上状態となり、耕盤が深くて過大な走行負荷がかかるようなときは、前輪３より車輪分担荷重の大きい後輪４が圃場に深く沈み込むことと後輪４の駆動反力との要因により、機体が前上がり姿勢になりやすいが、後輪４が下動状態となることで機体の前上がり姿勢が修正され、植付部７の沈下により苗植付姿勢が乱れたりするようなことを防止できる。一方、畦際での機体旋回時には、走行負荷が増大するので、自動的に後輪４が下動状態となることで機体が前下がり姿勢になり、機体旋回のために旋回内側の後輪４の駆動を断つことにより旋回外側しか駆動しない後輪４に対して左右両方を駆動させる前輪３の車輪分担荷重を増すことができ、ひいては前輪３の走行推進力を向上させることができ、旋回走行を円滑に行うことができる。また、前進での畦越え時や前進でのトラックへの積込時は、走行負荷が大きくなるため、後輪４が下動状態となって機体の前上がり姿勢が修正され、作業の安全性が図れる。また、畦越え時やトラックへの積込時でも機体が後上がり姿勢となる後進時は、後輪４が上動状態に維持され、後輪４が下動することにより機体が更に後上がり姿勢になることはなく、安全である。 As described above, with this rice transplanter 1, during normal planting, the rear wheel 4 is in the uppermost state under normal traveling load, and the wheel is deeper than the front wheel 3 when the plow is deep and an excessive traveling load is applied. Due to the factors that the rear wheel 4 with a large shared load sinks deeply into the field and the driving reaction force of the rear wheel 4, the aircraft tends to be in a front-up position, but when the rear wheel 4 is in the downward movement state, The forward raising posture is corrected, and it is possible to prevent the seedling planting posture from being disturbed by the settlement of the planting unit 7. On the other hand, since the traveling load increases at the time of turning the vehicle at the shore, the rear wheel 4 is automatically moved downward so that the vehicle is in a forward-lowering posture. The driving load of the front wheel 3 that drives both the left and right sides with respect to the rear wheel 4 that drives only the outside of the turn can be increased by cutting off the driving of the vehicle. Can be performed smoothly. Also, when traveling over the ridge or when loading on the truck during forward travel, the traveling load increases, so the rear wheel 4 moves downward and the front-up posture of the fuselage is corrected. Can be planned. In addition, the rear wheel 4 is maintained in the upward movement state when the aircraft is in the rearward raising posture even when over the ridge or when being loaded onto the truck, and the aircraft is further raised in the rearward posture by moving the rear wheel 4 downward. It will never be safe.

尚、前述のクッションゴム６０に代えて圧縮スプリングを設け、後輪伝動ケース３４の上下回動全域において前記圧縮スプリングを作用させる構成とすることができる。そして、後進時及び前進時でも後輪４の駆動負荷が小さい通常の走行時には圧縮スプリングが全圧縮状態となり、前進時で後輪４に所定以上の駆動負荷が生じたときには圧縮スプリングが伸長して後輪伝動ケース３４の下側への回動を付勢することができる。尚、この圧縮スプリングを設ける場合も、前述のようなクッションゴム６０を併用してもよい。 In addition, it can replace with the above-mentioned cushion rubber | gum 60, and it can be set as the structure which provides a compression spring and operates the said compression spring in the whole vertical rotation area of the rear-wheel transmission case 34. The compression spring is fully compressed during normal travel when the driving load of the rear wheel 4 is small even when the vehicle is moving backward and forward, and the compression spring is extended when a predetermined driving load is generated on the rear wheel 4 during the forward movement. The downward rotation of the rear wheel transmission case 34 can be urged. Even when this compression spring is provided, the cushion rubber 60 as described above may be used in combination.

尚、圧縮スプリングを設けるにあたり、前述の規制用アーム５８の外周に巻回されるように設け、一端が第三支持部材５５に当接して規制され、他端が規制用ピン５７に当接して後輪伝動ケース３４を下側に回動付勢する構成としてもよい。つまり、圧縮スプリングがその内部を通る規制用アーム５８で支持され、圧縮スプリングの外れを防止できると共に、構成の簡略化が図れる。 In providing the compression spring, the compression spring is provided so as to be wound around the outer periphery of the restriction arm 58, one end is in contact with the third support member 55, and the other end is in contact with the restriction pin 57. The rear wheel transmission case 34 may be configured to be biased downward. That is, the compression spring is supported by the restricting arm 58 passing through the inside thereof, so that the compression spring can be prevented from coming off and the configuration can be simplified.

尚、後輪４の上動又は下動を付勢する付勢手段となる圧縮スプリングを設けた構成において、その付勢力を可変させることにより、後輪４を下動させる負荷を任意に変更可能にし、変速レバーの切り替えによる機体「移動」（路上走行）時には後輪４を下動させず、「植付作業」時には機体前部が浮き上がるような高負荷時のみ後輪４を下動させて機体の後部を上昇させるように構成することで、駆動反力の小さい路上走行では後輪４を上下動させず、駆動反力の大きい圃場走行では必要以上に後輪４が上下動しないように抵抗を与えることが可能となる。 In addition, in the configuration provided with a compression spring that serves as an urging means for urging the rear wheel 4 upward or downward, the load for moving the rear wheel 4 downward can be arbitrarily changed by varying the urging force. The rear wheel 4 is not moved down when the machine is “moving” (running on the road) by switching the shift lever, and the rear wheel 4 is moved down only during high loads when the front part of the machine is raised during “planting”. By configuring the rear part of the aircraft to rise, the rear wheel 4 is not moved up and down when traveling on the road with a small driving reaction force, and the rear wheel 4 is not moved up and down more than necessary when traveling on a field with a large driving reaction force. It becomes possible to give resistance.

また、上記のような構成において、油圧式無段変速装置２７を駆動する変速レバ−３１の操作に起因する前後進低速時には後輪４を下動させず、中・高速時には機体前部が浮き上がるような高負荷時のみ後輪４を下動させるよう構成することもでき、駆動反力の小さい低速走行では後輪４を上下動させず、駆動反力の大きい高速走行では必要以上に後輪４が上下動しないように抵抗を与えることが可能となる。 Further, in the above-described configuration, the rear wheel 4 is not moved down at the time of forward / backward traveling due to the operation of the transmission lever 31 that drives the hydraulic continuously variable transmission 27, and the front part of the body is lifted at the middle / high speed. The rear wheel 4 can also be configured to move downward only during such a high load, and the rear wheel 4 is not moved up and down in low speed traveling with a small driving reaction force, and the rear wheel is more than necessary in high speed traveling with a large driving reaction force. It is possible to provide resistance so that 4 does not move up and down.

更に、エンジン１５のスロットル低回転時には後輪４を下動させず、中・高速時には機体前部が浮き上がるような高負荷時のみ後輪４を下動させて機体の後部を上昇させるように構成することもできる。 In addition, the rear wheel 4 is not moved down when the throttle of the engine 15 is low, and the rear wheel 4 is moved down to raise the rear part of the aircraft only at high loads where the front part of the fuselage is lifted at medium and high speeds. You can also

尚、前述のクッションゴム６０を後進高負荷時には圧縮して撓むような弾力特性に設定し、後進高負荷時には逆に機体後部を下降させて機体の前下がり状態を緩和させ、前輪３の沈み込みを防止することもできる。これによれば、後進での畦越えやアユミ越えが容易にでき、走行抵抗の大きい湿田での後進性能が向上する。 The above-described cushion rubber 60 is set to have elastic characteristics such that it compresses and bends when the vehicle is moving backward, and the rear part of the aircraft is lowered to relieve the vehicle from being lowered when the vehicle is moving backward. Can also be prevented. According to this, it is possible to easily go over the ridge and Ayumi in the reverse direction, and the reverse performance in the wet field having a large running resistance is improved.

また、ブレーキペダル３２の操作に連動して左右の後輪伝動ケース３４の上下回動を規制する規制具を設け、機体を走行停止させたときには後輪４が上下動しないように固定する構成とし、トラック等での運搬時にはペダル保持装置によりブレーキペダル３２を踏み込み状態で保持しておけば、運搬時の振動等により無闇に後輪４が上下動するようなことを防止でき、後輪伝動ケース３４の急激な上下動により後部フレーム４９や後輪伝動ケース３４が破損するようなことを防止でき、また荷台等に保持するために機体に掛けられたロープが引っ張られて緩んだり切れたりするようなことを防止できる。 Further, a restricting tool for restricting the vertical rotation of the left and right rear wheel transmission cases 34 in conjunction with the operation of the brake pedal 32 is provided, and the rear wheel 4 is fixed so as not to move up and down when the vehicle is stopped running. If the brake pedal 32 is held in the depressed state by the pedal holding device during transportation on a truck, etc., the rear wheel 4 can be prevented from moving up and down by vibration during transportation, and the rear wheel transmission case. It is possible to prevent the rear frame 49 and the rear wheel transmission case 34 from being damaged due to a sudden up-and-down movement of the 34, and the rope hung on the fuselage to be held on the cargo bed etc. is pulled and loosened or cut off. You can prevent anything.

１：４条植田植機（苗移植機）、２：車体、３：前輪、４：後輪、７：苗植付部、３３：後輪伝動軸、３４：後輪伝動ケース、３４ｂ：後輪伝動ケースの入力軸、５４：回動支点軸、５６：後輪車軸、５７：規制用ピン、５８：規制用アーム 1: 4-row Ueda transplanter (seedling transplanter), 2: vehicle body, 3: front wheel, 4: rear wheel, 7: seedling planting part, 33: rear wheel transmission shaft , 34: rear wheel transmission case, 34b: rear an input shaft of the wheel transmission case, 54: the rotation fulcrum shaft 56: rear wheel axle, 57: regulating pin 58: restricting arm

Claims

左右の前輪（３）及び左右の後輪（４）を備える車体（２）を設け、該車体（２）の後方には昇降可能な苗植付部（７）を設け、後輪車軸（５６）を備える後輪伝動ケース（３４）と該後輪伝動ケース（３４）の入力軸（３４ｂ）へ前側から伝動する後輪伝動軸（３３）とを設け、回動支点軸（５４）より後側に後輪車軸（５６）が位置するように前記後輪伝動ケース（３４）を前記回動支点軸（５４）回りに上下に回動可能に装着し、後輪伝動ケース（３４）の下側への回動を付勢する圧縮スプリングを設け、後輪伝動ケース（３４）の上下方向の回動域を規制する規制部材（５７，５８）を設け、前記圧縮スプリングを規制部材（５７，５８）の外周に巻回する構成とした苗移植機。 A vehicle body (2) having left and right front wheels (3) and left and right rear wheels (4) is provided, and a seedling planting portion (7) that can be raised and lowered is provided behind the vehicle body (2), and a rear wheel axle (56 ) rear wheel transmission shaft for transmission from the front and (33) provided to the input shaft of the wheel transmission case after having a (34) and the rear wheel transmission case (34) (34b), after the rotation fulcrum shaft (54) the rotation fulcrum shaft (54) pivotally mounted vertically around the rear wheel transmission case as the rear wheel axle (56) is located (34) on the side, below the rear wheel transmission case (34) A compression spring that urges rotation to the side, a restriction member (57, 58) that restricts the vertical rotation area of the rear wheel transmission case (34), and a compression member (57, 58) Seedling transplanter configured to be wound around the outer periphery .